Listen, this is the race. The race is going to be about trust vs. temperament. Clearly, she has some vulnerabilities on that score. He has big vulnerabilities on the other.

The question is, this is not new material that they are presenting relative to the Clintons. Some of this is new material relative to Trump, who people are just getting to know. So -- and the other issue is one of scale, because, as has been written about quite a bit lately, the Clinton campaign and allied forces have far more resources than the Trump forces do.

So we're giving equal weight to these ads here, but voters are not seeing them in equal numbers.

TAPPER: Who would you suggest that Hillary Clinton pick as her vice president? You have been through this process. You helped Obama pick Biden.

AXELROD: Yes.

My advice would not to be too venturesome, because I think what she's really selling now is reliability, is experience, and -- and so I would pick someone who reflects those qualities. Remember, this is the first presidential appointment, so it says a lot

about how you view governance. So, I would look at a guy like Senator Tim Kaine of Virginia, who has been a governor, who has been a mayor, who has been a Catholic missionary, and who is widely liked within the Democratic Party. He has governed a swing state and is a very solid guy who is not going to cough up the football.

But there are arguments for others, Julian Castro, the -- would bring something else, the secretary of HUD, who is among those she's apparently considering, young former mayor of San Antonio, Hispanic. Elizabeth Warren would be very, very welcome among the Bernie Sanders supporters within the party.

TAPPER: Whom would you recommend Donald Trump pick? Who would help him?

AXELROD: Well, the first question is, who is willing to serve?

A lot of people have taken them out of it. And if he has a few weeks like he had, he may have to put it up on Craigslist. But we know that Newt Gingrich has volunteered to do it, who is obviously bright and valuable and knowledgeable, plausible choice.

Chris Christie has seemed eager for that job. Obviously, both of them would be warriors on the stump for him. Mary Fallin, the governor of Oklahoma, would be an interesting choice, because she obviously is a woman.

But, again, the concern would be to expose someone to a national race, much as Sarah Palin was, who has never been through that before. And you know better than anyone the pressures that that entails. So, a Gingrich, a Christie are far more likely to stand up to those pressures than someone who has never faced them before.

TAPPER: All right, fair enough.

David Axelrod, thank you so much.

AXELROD: Good to be with you.

In a race where the two major party presumptive nominees are, to quote FiveThirtyEight, more strongly disliked than any nominee at this point in the past 10 presidential cycles, a third-party candidate may have an opportunity like never before.

Libertarian presidential nominee Gary Johnson, for example, ran for president in 2012. He got 1 percent of the vote that year, but today's polls show him ranking much higher. Could he be a real option?

TAPPER (voice-over): Gary Johnson says you might be a Libertarian, even if you don't know it yet.

JOHNSON: Help me reach out to the majority of Americans who All are Libertarian and don't know it.

TAPPER: Or at least the Libertarian presidential candidate hopes you will vote that way.

In their campaign, former Republican Governors Johnson from New Mexico and his running mate, Bill Weld from Massachusetts, are casting themselves as outsiders. And Johnson's style is a bit more like that stoner professor you had in college than a traditional candidate.

TAPPER: But there may be an opening. The two major party candidates are the least liked in modern history, helping Libertarians earn support from 9 percent of registered voters in a recent CNN/ORC poll, more than any third-party candidate at this point in the campaign in recent open elections.

UNIDENTIFIED MALE: No excuses, Libertarians.

TAPPER: The Libertarian Party was established in 1971. Despite a relatively high-profile presidential run by Congressman Ron Paul in 1988, Libertarians have consistently struggled to be seen as anything but fringe.

(on camera): Why should anybody vote for you, sir? How will it not be throwing away their vote?

JOHNSON: Well, throwing away your vote is voting for somebody that you don't believe in. But I think that Libertarians, I think my package, Bill Weld's package is really unique.

[16:35:06]

TAPPER (voice-over): Johnson is unique. He's a triathlete who has climbed Mount Everest and Kilimanjaro and is also the former CEO of a medical and recreational marijuana company.

JOHNSON: I have always maintained that legalizing marijuana will lead to less overall substance abuse.

TAPPER: The Libertarians say they lean left on social issues such as LGBT rights and abortion.

BILL WELD, LIBERTARIAN VICE PRESIDENTIAL CANDIDATE: I would like to ideally nudge the Democrats toward the economic center.

TAPPER: While promising to crack down on the national debt and cut corporate income tax.

Those who dislike Clinton and Trump are giving them a closer look.

MITT ROMNEY (R), FORMER PRESIDENTIAL CANDIDATE: If Bill Weld were at the top of the ticket, it would be very easy for me to vote for Bill Weld for president. So, I will get to know Gary Johnson better.

TAPPER: But the Libertarian still needs to earn 15 percent in national polls to make it to the presidential debate stage this fall, perhaps Johnson's steepest climb yet.

(END VIDEOTAPE)

TAPPER: Tonight, your chance to really get to know Gary Johnson and Bill Weld, the Libertarian ticket. Chris Cuomo will moderate tonight's CNN Libertarian town hall. That begins at 9:00 p.m. Eastern right here on CNN.

Coming up, as more people share their accounts of the Orlando terrorist attack, there are some new questions about the timeline of the police response, one officer now telling his harrowing story. Stay with us.

(COMMERCIAL BREAK)

[16:40:48]

TAPPER: Welcome back to THE LEAD. I'm Jake Tapper.

Our national lead now. New questions today raised about the initial police response to the Orlando nightclub shooting, after law enforcement first arrived on the scene and engaged the terrorist, this as we're also getting a more complicated picture of the Orlando mass murderer and what may have specifically motivated him to kill 49 people in cold blood.

CNN's Ed Lavandera joins me now live from Orlando.

Ed, what about the law enforcement response is coming under scrutiny today?

ED LAVANDERA, CNN CORRESPONDENT: Well, one of the things that they are looking at is the timing and the movements of the officers that were inside the club.

(BEGIN VIDEOTAPE)

LAVANDERA (voice-over): When Omar Mateen first shot his way into the Pulse nightclub, he exchanged gunfire with a security guard, but within six minutes, a small group of officers arrived and burst inside the club.

UNIDENTIFIED MALE: Our officers were within the club within minutes and engaged the suspect in gunfire. And that's important because that engagement and that initial entry caused him to retreat, stop shooting and barricade himself in the bathroom with hostages. LAVANDERA: One of those officers, Brandon Cornwell, tells "The

Washington Post" that instead of charging into the bathroom where Mateen murdered a number of victims -- quote -- "They told us to retreat, that they'd take over because we were not really in tactical gear. We were just in our police uniforms."

Cornwell, a Belle Isle police officer, did not, however, criticize the decision to wait for the SWAT teams to move inside. Orlando police officials would not verify the officer's account and said first- responder actions will be scrutinized in a detailed after-action report.

UNIDENTIFIED MALE: I'm extremely proud of the heroic action of our officers, and I'm very confident they saved many, many, many lives that night.

LAVANDERA: Investigators continue looking into Omar Mateen's background, specifically looking into the possibility that the terrorist was gay.

QUESTION: Several people have come forward and said that they had same-sexual relationships with Mateen. Are you interviewing those people?

LORETTA LYNCH, U.S. ATTORNEY GENERAL: If individuals come forward with any information involving contact with him, they are individuals that we would be interested in interviewing. I'm not going to be able to give you the specifics of who we are talking to right now, because that's part of the ongoing investigation. We're trying to find out essentially all motivations he may have had.

LAVANDERA: And the man who first alerted the FBI about Mateen in 2014 says he did so because he heard Mateen talking about watching videos of a radical Muslim cleric.

UNIDENTIFIED MALE: My reaction to him was what he thought about the videos. And he told me they were powerful. Both of those raised a red flag for me and prompted me to speak with the FBI.

(END VIDEOTAPE)

LAVANDERA: And, Jake, investigators have finished their work at the Pulse nightclub. The roads have been reopened.

And over the last day or so, we have seen a steady stream of people coming here. This is the closest that they have been able to the nightclub, leaving flowers and remembrances here just outside the club -- Jake.

TAPPER: Ed Lavandera, thank you so much.

North Korea conducting two missile launches, and this time, they have shown a dangerous capability that we have not seen from them before. U.S. officials are now worried about what is next.

(COMMERCIAL BREAK) [16:46:03] TAPPER: Welcome back to THE LEAD. I'm Jake Tapper. In

today's World Lead today, North Korea test firing two ballistic missiles overnight, rattling the region and much of the world. These latest provocations mark the fifth and sixth attempts over the last two months and they are the most successful launches by Kim Jong-Un's regime this year.

U.S. officials fear North Korea could mount a nuclear payload to the mobile mid-range missile and that would mean U.S. territories would be within striking distance.

Let's get right to CNN's Barbara Starr live at the Pentagon for us. Barbara, this represents significant improvement in North Korea's weapons program, yes?

BARBARA STARR, CNN PENTAGON CORRESPONDENT: This is the first for the regime, Jake. It was that sixth missile, the second to be launched that flew 250 miles off North Korea's east coast into the Sea of Japan. This missile flowing 250 miles achieved an altitude and came back down into the atmosphere.

What does all of that means? It means that North Korea, for the first time, has really successfully tested a mobile missile that could someday have a nuclear warhead on top of it. Why is a mobile missile so significant?

Because you put it on a mobile launcher, you fire it and then you move the launcher to some other location very quickly. In war time, it makes it extremely difficult for U.S. spy satellites to potentially keep track of where these North Korean launchers may be. It's the old shoot and scoot that we've heard about for so many years.

So this is a significant development for it. If this missile eventually works, it would have the range eventually to reach Guam, the outer islands of Alaska. Bottom line, North Korea has now demonstrated capabilities in an intercontinental ballistic missile, a nuclear head, and now a mobile missile.

[16:50:05]TAPPER: Alarming news. Barbara Starr, thanks so much.

Let's turn now to our Health Lead. One of the most prominent athletes in the world is dropping out of the 2016 Rio Olympics over Zika fears. Top golfer, Rory McIlroy announced he will not be competing in Rio saying in a statement, quote, "I've come to realize that my health and my family's health comes before anything else.

Even though the risk of infection from the Zika virus is considered low, it is a risk nonetheless and a risk I am unwilling to take." Zika is transmitted by mosquitoes and through sexual contact that's been linked to devastating growth defects such as microcephaly in newborn babies when pregnant women are infected. It can also cause in adults a severe neurological disorder that can even lead to paralysis.

Some are calling it the U.K.'s Donald Trump's movement. What could the candidate and his supporters tell us about the drive to get Great Britain out of the E.U. and what does that mean for the United States? (COMMERCIAL BREAK)

[16:55:30]

TAPPER: Welcome back to THE LEAD. I'm Jake Tapper. In our Money Lead today, is the United Kingdom pulling a Donald Trump? Many Britons, like many Trump supporters are angry and frustrated over unemployment, immigration problems, and the general feeling that their politicians are not working for them.

And many in the U.K. think that leaving the European Union could help fix those problems. In our latest installment of the series we're calling "America's Debt and The Economy," voters in Britain are just hours away from having their say on the acrimonious so-called Brexit referendum.

Brexit stands for Britain exit. Before you ask yourself, now why do I care whether the U.K. stays in the E.U. or not. You should know that tomorrow's vote, tomorrow's decision could potentially have powerful ripple effects, not only on the global economy but here at home.

Let's bring in CNN business correspondent, Alison Kosik. Alison, what kind of implications can Americans expect if Britain leaves the E.U.?

ALISON KOSIK, CNN MONEY CORRESPONDENT: You know, Jake, you think about this referendum happening thousands of miles from the U.S., but if the British people vote for Britain to leave the E.U., it could affect us here at home. You'll feel it everywhere from your mortgage to your 401(k).

(BEGIN VIDEOTAPE)

KOSIK (voice-over): What happens in Europe doesn't stay in Europe.

JANET YELLEN, FEDERAL RESERVE CHAIR: A U.K. vote to exit the European Union could have significant economic repercussions.

KOSIK: With the global economy, more interconnected than ever, a vote for Brexit could deliver a shock to Europe, one that could also be felt in the United States, most immediately, in the stock market.

KEITH BLISS, SENIOR VICE PRESIDENT, CUTTONE & CO.: This is a tsunami. This is China melting down. This is going out of business.

KOSIK: In the week following a vote for Brexit, one analysis predicts the S&P 500 would see a 5 percent slump and a 40 percent spike in volatility.

BLISS: It will hit the 401(k)s because money rushes to safety assets and that is not cash equities.

KOSIK: But a stock market decline isn't the only problem. If it's no longer in the E.U., the U.K. would need to negotiate new trade deals, which could take years. A major headache as the U.K. is America's seventh biggest trading partner. BARACK OBAMA, PRESIDENT OF THE UNITED STATES OF AMERICA: Our focus is in negotiating with a big block of the European Union to get a trade agreement done and U.K. is going to be in the back of the queue.

KOSIK: If trade and investment suffer that could push Britain into a recession and then the big fear becomes contagion. Would Europe and the U.S. be next?

YELLEN: I don't think that's not the most likely case, but we don't know what will happen and we'll have to watch for it very carefully.

KOSIK: The pro-Brexit camp says it's the right move in the long run.

UNIDENTIFIED MALE: It would be unsurprising if there were some short term costs. I think it's perfectly reasonable point to concede, but it's actually about the long-term interests of the U.K.

KOSIK: Also watching, American companies that do business overseas like JP Morgan. They could cut jobs.

UNIDENTIFIED MALE: I don't know if it means a thousand jobs, 2,000 jobs, it could be as many as 4,000.

(END VIDEOTAPE)

KOSIK: There is one cost of effect, if there is Brexit, it could make it cheaper to finance your house because mortgage rates could go even lower that's because you'll see investors flock to safe haven investments like U.S. Treasuries and that would push overall interest rates lower.

The bad news, your 401(k) could take a really big hit. I'm talking a big hit at the opening bell on Friday as investors try to get a handle on what the bigger meaning is of a possible Brexit --Jake.

TAPPER: All right, Alison Kosik, thank you so much.

The Sports Lead now. He went from king to god in Cleveland when he ended the city's half-century long championship drought and this is the thanks Lebron James will get for that. Fans found out that this iconic football field-sized Lebron James banner will be coming down for Donald Trump and the Republican convention in about a month.

Now, the owner of the space has announced that it will be going back up after the Republicans leave town. Of course, there are many, many Republicans hoping that Lebron James will swoop into the convention and do what he did to Andre Igoudala to save game seven and block Trump from being nominated. But those of course are pipe dreams by a writer on my staff who smokes too much marijuana.

Be sure to follow me on Facebook and on Twitter @jaketapper or tweet the show @theleadcnn. That's it for THE LEAD. I'm Jake Tapper turning you over now to Wolf Blitzer in "THE SITUATION ROOM."